public class SaleItem {
    private double _cost;
    private int _num;

    public SaleItem(double cost, int num) {
        _cost = cost;
        _num = num;
    }

    public double get_cost() {
        return _cost;
    }

    public void set_cost(double _cost) {
        this._cost = _cost;
    }

    public double get_num() {
        return _num;
    }

    public void set_num(int _num) {
        this._num = _num;
    }
}
